Preface This is the first edition of CSA N290.13, Environmental qualification of equipment for CANDU nuclear power plants. The requirements for environmental qualification (EQ) of safety-related equipment in CANDU nuclear power plants are specified in the CSA N290 series of Standards. General quality assurance requirements for the life cycle of these plants are specified in the CSA N286 series of Standards. This Standard is supplemental to these two series of Standards. Scope 1.1 This Standard specifies the requirements for an environmental qualification (EQ) program for CANDU nuclear power plants (see Figure 1). The program comprises a set of planned and coordinated activities that establishes auditable assurance that the equipment required to perform safety functions will meet or exceed the functional and performance requirements under accident conditions, taking into consideration the effects of normal service. 1.2 This Standard addresses the effects of aging on equipment required to mitigate the effects of a design basis accident and addresses the need to minimize common mode failure under accident conditions. The methodology presented for establishing and preserving environmental qualification will confirm the adequacy of the equipment to meet its design requirements. 1.3 The requirements established herein are to be used for the preservation of qualification during maintenance or modification of equipment and systems and are to be used in the procurement of equipment and parts. 1.4 Other CSA Standards may provide qualification requirements for specific equipment. These Standards should be used in conjunction with this Standard. In the event of any conflict between this Standard and other Standards referenced herein in regard to the specific requirements for environmental qualification, the requirements of this Standard apply. 1.5 Seismic considerations are not included within the scope of this Standard, except during equipment qualification testing (see CSA CAN3-N289.1). 1.6 In CSA Standards, \"shall\" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; \"should\" is used to express a recommendation or that which is advised but not required; \"may\" is used to express an option or that which is permissible within the limits of the standard; and \"can\" is used to express possibility or capability. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.